问向视图中当前元素的li项添加类

EN

<ul class="features">
<li class="active"><a href="#block1">block 1</a></li>
<li class="active"><a href="#block2">block 2</a></li>
<li class="active"><a href="#block3">block 3</a></li>
<li class="active"><a href="#block4">block 4</a></li>
</ul>

<div id="block1">my content....</div>
<div id="block2">my content....</div>
<div id="block3">my content....</div>
<div id="block4">my content....</div>

$('.menu-features li > a').click(function() {
$('.menu-features li').removeClass();
$(this).parent().addClass('active');
});

$('a[href^="#"]').click(function() {
$('html,body').animate({ scrollTop: $(this.hash).offset().top-120}, 700);
return false;
e.preventDefault();
});

$('#block3').waypoint(function(direction) {
    $('.menu-features li').addClass('test')
});